Recommended Alignment Specs?

Only PART of what works on a standard Solo II set-up doesn't, as you have indicated, work on a street car. The Prius spec, as I recall, is for zero to slight toe-in. I know from experience that toe-out isn't a good thing for stability, making the Prius darty and more succeptable to following rain grooves (although tires seem to have more effect on the latter). I also seem to remember the Prius calls for a little negative camber, which is good on the street and on the track (although for the track, more is better - we ran 2 degrees negative camber front on our Neon ACR). Caster depends a lot on front end geometry, although from a pure theory standpoint, positive caster reduces straight-line stability and makes turn-in quicker (good for the track) while negative caster increases on-center stability and increases turn-in reaction time (good for the highway).

In any case, I'd go with stock (which I did on mine) with critical attention paid to getting the toe-in at zero or VERY SLIGHTLY in (less means less wear). It made a world of difference on mine. Also set the camber to the negative limit of the spec.